Slow Transit Constipation: Symptoms, Diagnosis, Treatments

Reviewed By: Pramod Kerkar, MD, FFARCSI

Person is considered to be constipated when he or she has less than or equal to two bowel movements in a week with hard and dry stools. Slow transit constipation occurs due to decreased intestinal motility as a result of abnormality of the enteric nerve. This condition is attributed to disordered colonic function. This type of constipation is intractable and doesn’t easily respond to fibers or laxatives and hence comparatively tough to treat.

What Is Slow Transit Constipation?

Slow Transit Constipation occurs when there is decreased large intestinal motility as a result of abnormality of the enteric nerve. Slow transit constipation has been traditionally classified and considered as a functional disorder. The term Slow Transit Constipation or STC was ﬁrst put forth in 1986 when a group of females who all had normal colons showed slow total gut transit time along with many other symptoms. Patients with slow transit constipation represent 15-30% of all constipated patients. It is very common in young women. The reason is not known for this.

The colon is 3 to 5 feet long with layers of muscles lining its wall. The muscle contractions produce movement, which help the stool to pass through the colon and out of the body. Small intestine empties the liquid stool in to the colon. The mechanism of the colon is to pull out water from the stool to make it firm. Peristalsis movements help pushing the stool towards its exit point i.e. the rectum. Once the stool hits the rectum, it starts to distend the rectum developing an urge to defecate. The communication between the muscle fibres and the brain is done through the nerves by way of neurotransmitters. The messages sent by these neurotransmitters are then received by the receptors in the muscle tissue. A muscle contraction occurs when these receptors are stimulated.

Some studies have suggested that children with slow transit constipation have abnormal messengers in the muscular layer of the intestinal walls to include peptide which is vital for peristalsis. Research also indicates that the nerve cells of the bowel may be abnormal in number, position or appearance. Constipation in most cases is observed a short while after the child has been toilet trained. The stools may be so hard that it may cause pain while defecating which then prohibits the child from completely defecating. The child tries to prevent defecation by contraction of the pelvic floor muscles and anal sphincter. The condition may worsen rapidly if corrective measures are not taken such as stool softeners to make bowel movements more smooth and pain free.

Symptoms Of Slow Transit Constipation

Slow transit constipation has a spectrum of variable severity. The list of symptoms of slow transit constipation is as follows:

Diagnosis Of Slow Transit Constipation

Slow transit constipation can be diagnosed soon after birth. The bowel motion that a child has immediately after birth is not a true bowel movement but is termed meconium fluid which is a dark glue like substance most of which is made up of mucus which protected the bowel lining of the baby before birth. If the newborn does not pass this fluid even after a day of life this possibly could warrant further investigation to check for Slow Transit Constipation. The diagnosis of STC first involves confirming slow transit of feces with studies conducted using a marker. This study involves the patient swallowing a capsule containing either radiolabelled or opaque numbered markers that glow on a series of x-rays taken over a span of a week to see if the bowel gets distended due to excessive accumulation of feces.

Barium enema, a special contrasting liquid is flushed into the bowel via the anus and x-rays are taken.

A more specialized diagnosis of slow transit constipation involves the following:

A detailed assessment by a specialist to look for a distended abdomen with discomfort which is classic for STC.

A positive NTS or Colonic Nuclear Transit Study in which the child swallows a radioactive element and its passage is tracked especially when it moves through the intestines for up to three days.

Laparoscopic biopsy – A small nick is made on the abdomen at three spots and tissue samples are taken of the bowel to look for any abnormalities in the muscle and nerves which may be causing STC.

It is very important and crucial to exclude other similar disorders which can mislead the treatment. For example, short-segment Hirschsprung’s disease can be excluded by taking a full-thickness rectal biopsy. A real-time x-ray taken during defecation will help suggest which condition is actually responsible for the constipation.

Treatment Of Slow Transit Constipation

Slow transit constipation can be controlled and the treatment options are following:

Medical management. Medications to improve bowel motility can be given to patients suffering from Slow transit constipation. Stimulant laxatives such a bisacodyl are considered first-line therapy. This can be combined with an osmotic laxative such as lactulose. There is no evidence to suggest that chronic use of such laxatives is harmful. Periodic use of bowel preparation solutions such as polyethylene glycol (Glycoprep®) may be needed.

Surgery. Surgery for treating slow transit constipation is a last resort. Surgery is indicated only in severe cases of Slow transit constipation that have failed other management options. The surgical options include:

Sacral nerve stimulator resulting in alteration of the nervous system of the colon.

Chait tube caecostomy which permits both decompression for the bloated colon (megacolon) and also allows for washout of the colon with water and antegrade enemas.

However, it is not always possible to treat slow transit constipation with surgery as too much of bowel may be affected.

Biofeedback. This is the most effective type of treatment option for slow transit constipation. This is a risk-free approach and has been very effective in the patients with slow transit constipation. The uncontrolled defecation is due to poor coordination between pelvic floor muscles and the abdominal muscles to eliminate stools from the body. This therapy teaches coordination of abdominal and pelvic muscles, and proper positioning which encourages evacuation. It also helps you form practices to promote regularity. Several trials have shown that this approach is not only efficacious but is superior to other treatment methods of slow transit constipation.